IRF1 and infection: Similar levels of cell death and interleukin 18 (IL-18) release were observed in WT and IRF1-deficient BMDMs in response to infection with S. Typhimurium (Fig. 1, A–C) and P. aeruginosa (Fig. 1, D–F), suggesting that IRF1 is dispensable for cell death and IL-18 release under these conditions.